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Institut für Astronomie und Astrophysik

Abteilung Astronomie

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orbitplot Source code in orbitplot.pro


       make plot of orbit in binary star system. Observers look at
       the orbit from the left and the companion circles the star in
       the clockwise direction
Calling Sequence
Input Parameters

Optional Input Parameters
      a     : semimajor axis of the orbit (default: 1.)
      eccen : Eccentricity of the orbit (default: 0.)
      lonasc: Longitude of ascending node (capital Omega; radians; default:0)
      incl  : Inclination (radians; not used; default: 0.)
      omega : Longitude of periastron (little omega; radians,
              default: 0.)
      position: position of figure in normal coordinates
      space  : fraction of free space around the ellipse (default: 0.05)
      units  : length unit of the plot (i.e., units of semimajor
      xtitle, ytitle: title for the x- and y-axis.
              Default (x-, and y-), if set, the units-keyword is ignored
      starrad: radius of the star (same units as semi-major axis)
              if given, a filled circle with radius starrad is drawn,
              if not, a dot at (0,0) designating the position of the
              star is plotted (default; but see keyword nostar)
      starname: name of the central star, overplotted on the star
              (unless nostar-keyword is given)
      phase1: phases to plot symbols on orbit (can be array)
      phase2: ending phase of highlighted orbit segment
              (if phase1 and phase2 are given, draw segment from phase1
              to phase2, NOTE: in this case phase1 must be scalar)
      phasethick: thickness of highlighted ellipse segment (default: 3)
      posdash : draw line perpendicular to ellipse at start and stop
                of highlighted orbit segment
      dirarrow: draw an arrow indicating the direction of motion
                from phase1 to phase2 (note phase2 MUST be greater
                than phase1)
      orbitcol: color for the orbit segment
      compsymbol: symbol to be plotted at the position of the stellar
                  companionorbit, works only if phase2 is not defined
                  (see IDL Help for PSYM, default: 0 (cross))
      symbolsize: sets symbolsize of input compsymbol (default: 1.0)
      shownodes: shows the line of nodes via a dotted line
Keyword Parameters
      nostar: if set, no position or circle is plotted at the
              stellar position
      degrees: if set, the angular input parameters are in DEGREES
      periastron: if set, draw triangular symbol at periastron
      oplot  : if set, the ellipse is drawn in the currently setup
               coordinate system (e.g., for plotting many cometary
      nodata : just setup the figure, do not plot the ellipse
  furthermore, the routine also accepts all keyword parameters of the
  plot and oplot commands via the _extra mechanism, thus allowing one
  to plot, e.g., colored orbits or change the thickness of the
  ellipse that is to be plotted
Output Parameters
Side Effects
      a plot is drawn
      the eccentricity must be less than unity; parabolic or
      hyperbolic orbits are not allowed at the moment.
      the ellipse coordinates are computed, then the bounding box
      is determined and the coordinate system is setup in a way that
      the x- and y-coordinates have the same length
 Orbits of the inner solar system:
 ; Mars
 orbitplot,a= 1.524,eccen=0.093,incl= 1.85,lonasc= 49.58, omega=336.0
 ; Mercury
 orbitplot,a= 0.387,eccen=0.206,incl= 7.00,lonasc= 48.33, omega= 77.5,/oplot
 ; Venus
 orbitplot,a= 0.723,eccen=0.007,incl= 3.39,lonasc= 76.68, omega=131.5,/oplot
 ; Earth
 orbitplot,a= 1.000,eccen=0.017,incl= 0.00,lonasc=-11.26, omega=102.9,/oplot
 Orbits of the outer solar system:
 ; Pluto
 orbitplot,a=39.482,eccen=0.249,incl=17.14,lonasc=110.30, omega=224.1
 ; Jupiter
 orbitplot,a= 5.203,eccen=0.048,incl= 1.31,lonasc=100.56, omega= 14.8,/oplot
 ; Saturn
 orbitplot,a= 9.537,eccen=0.054,incl= 2.48,lonasc=113.72, omega= 92.4,/oplot
 ; Uranus
 orbitplot,a=19.191,eccen=0.047,incl= 0.77,lonasc= 74.23, omega=171.0,/oplot
 ; Neptune
 orbitplot,a=30.069,eccen=0.009,incl= 1.77,lonasc=131.72, omega= 45.0,/oplot
 Make PNG of the Vela X-1 system
 orbitplot,eccen=0.1885,a=53,omega=150.6,units=textoidl('R_O'), $
   starrad=30.,/degrees,/periastron,starname='HD 77581', $
Revision History
 $Log: orbitplot.pro,v $
 Revision 1.5  2005/02/22 15:55:05  wilms
 replaced keyword arrowdir with dirarrow, since it produced a clash
 with IDL's keyword abbreviation mechanism.
 Revision 1.4  2005/02/18 23:28:54  wilms
 added shownodes, arrowdir, phasethick, posdash, nodata and _extra keywords
 Revision 1.3  2003/04/01 07:41:58  gleiss
 added optional inputs compsymbol and symbolsize
 Revision 1.2  2002/09/19 20:55:50  wilms
 added option to highlight orbital segment or specific phases
 Revision 1.1  2002/09/09 14:53:28  wilms
 initial release
 CVS Version 1.3 2003/04/01 gleiss
 added optional inputs compsymbol and symbolsize

Last modified by pro2html on 2005 February 23 at 04:11 UTC

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Jörn Wilms (wilms@astro.uni-tuebingen.de)
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